The present invention relates to an apparatus for forming a coating film for coating a sol on a substrate for forming a dielectric film and to an apparatus for aging a sol-state coating film to change to a gel-state coating film.
A manufacturing process for a semiconductor device includes a step of forming an interlayer dielectric film on a metal wiring layer or between the metal wiring layers made of aluminium or copper. The interlayer dielectric film is known to be formed by various methods including a Sol-Gel method, a SiLk method, a SPEED FILM method, and a FOx method.
In the Sol-Gel method, a sol (colloid solution) having TEOS (tetraetoxysilane; Si(OC2H5)4) dispersed in an organic solvent, is spin-coated on a surface of a semiconductor wafer. Then, the coated sol is changed into a gel (Gel process). Furthermore, the solvent in the coating film is replaced with another solvent (solvent exchange process), dried and baked. Through these steps, a desired interlayer dielectric film is obtained. In the gelation step, for example, ammonia is used as a chemical solution. In the solvent exchange process step, ammonia or hexamethyldisilazane (HMDS) is used as the chemical solution.
The gel process is performed in an aging unit of the SOD (Spin on Dielectric) system. The process chamber of the aging unit is surrounded by a heating plate and a cover. The semiconductor wafer coated with a sol is first mounted on the heating plate. The process chamber is evacuated while ammonia is supplied into the process chamber, and a semiconductor wafer is heated by the heating plate, to e.g., 100xc2x0 C. Through these steps, the coating film formed on the semiconductor wafer is changed from a sol to a gel.
The cover of the aging unit is vacuum-adsorbed to the heating plate by a vacuum adsorption mechanism. Therefore, when an inner pressure of the process chamber is significantly larger than an adsorption pressure of the vacuum adsorption mechanism, or when the inner pressure of the process chamber significantly decreases and becomes almost equal to the adsorption pressure of the vacuum adsorption mechanism, ammonia within the process chamber may leak outside. Since ammonia has a destructive effect on other processes including a post exposure baking (PEB) unit for a chemically amplified resist, leakage of ammonia outside from the aging unit must be prevented.
An object of the present invention is to provide an apparatus for forming a coating film and an aging process apparatus capable of preventing leakage of gas from a process chamber even if an inner pressure of the process chamber greatly changes.
According to the present invention, there is provided an apparatus for forming a coating film, comprising:
a coating unit for coating a sol containing dielectric particles and a first solvent on a substrate;
an aging unit for changing a sol-state coating film formed on the substrate in the coating unit to a gel state; and
a solvent exchange unit for applying a second solvent different from the first solvent to the coating film to replace the first solvent in the coating film with the second solvent,
wherein the aging unit comprises
a heating plate for heating the substrate;
a cover arranged in contact with a peripheral portion of the heating plate to form a process chamber surrounding the substrate, together with the heating plate;
a vacuum adsorption mechanism for vacuum-evacuating a contact surface between the cover and the heating plate to thereby adsorb the cover to the heating plate;
a chemical solution vapor supply mechanism for supplying a chemical solution vapor to the process chamber;
an evacuation mechanism for evacuating the process chamber to set an inner pressure of the process chamber at a negative value; and
a process chamber pressure monitor for detecting an inner pressure of the process chamber.
According to the present invention, there is provided an aging process apparatus for receiving a substrate coated with a sol containing dielectric particles and a solvent and changing the sol-state film to a gel state film, comprising
a heating plate for heating the substrate;
a cover arranged in contact with a peripheral portion of the heating plate to form a process chamber surrounding the substrate, together with the heating plate;
a vacuum adsorption mechanism for vacuum-evacuating a contact surface between the cover and the heating plate to thereby adsorb the cover to the heating plate;
a chemical solution vapor supply mechanism for supplying a chemical solution vapor to the process chamber;
an evacuation mechanism for evacuating the process chamber to set an inner pressure of the process chamber at a negative value; and
a process chamber pressure monitor for detecting an inner pressure of the process chamber.
According to the apparatus of the present invention, it is possible to detect the inner pressure of the process chamber by the process chamber pressure monitor. Therefore, since the abnormal inner pressure can be detected immediately upon the occurrence, on the basis of the obtained pressure detection data, it is possible to prevent leakage of the chemical solution vapor from the process chamber before the occurrence.
Furthermore, the aging unit preferably comprises
an inert gas supply mechanism for supplying an inert gas to the process chamber; and
control means for outputting an instruction signal to the chemical solution vapor supply mechanism for terminating supply of the chemical solution vapor; an instruction signal to the inert gas supply mechanism for initiating supply of an inert gas, and an instruction signal to the evacuation mechanism for evacuating the process chamber, when the process chamber pressure monitor detects a predetermined uppermost permissible pressure value or a predetermined lowermost permissible pressure value.
Furthermore, the aging unit preferably comprises
alarm means for giving an alarm when the process chamber pressure monitor detects a predetermined uppermost permissible pressure value or a predetermined lowermost permissible pressure value. Therefore, it is possible for an operator to deal with the abnormality immediately upon hearing the alarm. As a result, it is possible to inhibit enlargement of leakage before the chemical solution vapor leakage reaches other processes.
Furthermore, it is preferable that the aging unit should have an adsorption pressure monitor for detecting an adsorption pressure of the vacuum adsorption mechanism. In this case, it is further preferable that the aging unit should comprise
an inert gas supply mechanism for supplying an inert gas to the process chamber; and
control means for outputting an instruction signal to the chemical solution vapor supply mechanism for terminating supply of the chemical solution vapor, an instruction signal to the inert gas supply mechanism for initiating supply of an inert gas, and an instruction signal to the evacuation mechanism for evacuating the process chamber when the process chamber pressure monitor detects a predetermined uppermost permissible pressure value or a predetermined lowermost permissible pressure value.
Further, in this case, the aging unit preferably comprises an alarm means for giving an alarm when the process chamber pressure monitor detects a predetermined uppermost permissible PRESSURE value or a predetermined lowermost permissible pressure value.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.